Generally, semiconductor devices are used in a variety of electronic applications, such as computers, cellular phones, personal computing devices, and many other applications. Semiconductor devices are manufactured by depositing many different types of material layers over a semiconductor workpiece or wafer, and patterning the various material layers using lithography. The material layers typically comprise thin films of conductive, semiconductive, and insulating materials that are patterned and etched to form integrated circuits (ICs). There may be a plurality of transistors, memory devices, switches, conductive lines, diodes, capacitors, logic circuits, and other electronic components formed on a single die or chip, for example.
Typically semiconductor devices operate at different operating conditions than conventional devices that store or transfer energy. For example, many semiconductor devices operate at much lower voltages than the conventional battery voltage or power transmission voltage. In many applications, transformers help to make the transition between different operating voltages by converting electricity at one voltage to electricity at another voltage, either of higher or lower value. A transformer achieves this voltage conversion using a primary coil and a secondary coil, each of which comprise a number of turns of an electrical conductor. The primary coil is connected to a source of voltage and the secondary coil is connected to a load. The ratio of turns in the primary coil to the turns in the secondary coil (turns ratio) is about the same as the ratio of the voltage of the source to the voltage of the load.
In many applications, transformers are integrated with the semiconductor device having the primary circuits. In such technologies, transformers are fabricated in metallization layers of a single chip and function to transfer signal and power. However, integration of a transformer on a single chip is challenging. For example, high electric fields exist between the primary and secondary coil which can result in reliability problems. Successful integration of transformers requires overcoming these and other problems.